Intermittent driving device for a timer mechanism



Dec. 31, 1963 H. 'r. SIMMONS 3,115,785

INTERMITTENT DRIVING DEVICE FOR A TIMER MECHANISM Filed Oct. 18, 1960 2 Sheets-Sheet 1 IN VEN TOR. l/AWOLfl 7t s/MMolvs Dec. 31, 1963 H. T. SIMMONS 3,115,735

INTERMITTENT DRIVING DEVICE FOR A TIMER MECHANISM Filed Oct. 18, 1960 2 Sheets-Sheet 2 INVENTOR. HAROLD 77 JYMMOMS ATTORNEY United States Patent Ofiice 3d 135,785 Patented Dec. 31, 1963 3,115,735 INTEFMHTTENT DRTVTNG DEVTCE FOR A TTMER MEtIHANlSM Harold T. Simmons, Warsaw, N.Y., assignor to Mallory Timers Company, a Division of P. R. Mallory dz Co., Inc, Indianapolis, End, a corporation of Delaware Filed Get. 18, 196% Ser. No. 63,357 Claims. (Cl. 74-125) This invention relates generally to intermittent driving devices for moving a ratchet wheel in discrete steps at determined intervals and is particularly directed to such devices associated with timing mechanism for activating a series of electric circuits in a predetermined program for an apparatus such as a washing machine and the like. The term escapement as used herein is defined to mean intermittent driving device for a timer mechanism.

Most intermittent driving mechanisms or devices used with timing devices include means for the storage of energy during a wind up cycle and for releasing the energy during the driving stroke. The means for storing energy to be released as a driving torque for a ratchet wheel is usually a spring which when either pulled or compressed stores enough energy to be transmitted to the ratchet through its cooperating driving mechanism.

in the use of such an intermittent driving mechanism, a prime function is to make the break the switch contacts at a speed which will prevent the contacts from destroying themselves by arcing due to their improper operation. As stated, the intermittent driving mechanism furnishes an output to associated equipment at predetermined intervals by the storage of energy in its driving member. This energy is released over a short period of time to a ratchet wheel and then to a cam contact activating assembly controlling the switching circuits. This time interval, however, must be fast enough for a quick make and break of the contacts but not so fast that shock may be induced into the switching mechanism with consequent deleterious effects.

Thus, the present intermittent driving mechanism provides means for accomplishing fast make or break contact action without introducing shock in the mechanism. It is an object of the present invention to provide an advancement mechanism in an intermittent timing device having improved operating characteristics.

Still another object of the present invention is to provide a step by step driving mechanism in a sequential timer having improved characteristics of accuracy and reliability.

Yet anotier object of the present invention is to provide a driver for a ratchet wheel wherein the energy supplied thereto is of such constancy as to assure proper operation of associated equipment.

Still another object of the present invention is to provide a constant torque advancement mechanism which is easy to fabricate and assemble.

- Still another object of the present invention is to proide an advancement mechanism for driving a ratchet in a constant manner, said mechanism including a minimum of parts and giving an improved eihciency and operational characteristic.

Yet another object of the present invention is the provision of an improved driving mechanism construction capable of a constant torque output activating a cooperating ratchet wheel and while preventing shock to the cooperating mechanism at the moment of energy release to the ratchet wheel.

It is also an object of the present invention to obtain an intermittent driving mechanism having optimum reliability characteristics afforded by a construction having a minimum of parts.

These and other objects and features of the invention are pointed out in the following description in terms of the embodiment thereof which is shown in the accompanying drawings. It is to be understood, however, that the drawings are for the purpose of illustration only and are not designed as a definition of the limits of the invention, reference being had to the appended claims for this purpose.

Referring now to the figures of the drawing, FIG. 1 is a perspective view of an embodiment of the advancement mechanism invention used in a sequential timer switch disclosing the constructional and operational fea tures thereof.

FIG. 2 is a view of the embodiment of the invention adapted to show the position of the arm with respect to the ratchet and its guidance channel while the spring is being stretched to store energy therein on the rise portion of the cam.

FIGS. 3 and 3a illustrate the placement of the cam with respect to the guidance channel directing the ratchet moving arm of the advance mechanism; the relative position of the channel with respect to the cam determining the drop off speed of the ratchet arm from the top portion of the cam surface.

FIG. 4 is a View of an alternative embodiment of the advancement mechanism invention shown in FIG. 1 and which uses a pull arm construction.

Generally speaking, the present invention provides an advancement mechanism in an intermittent driving device included in a cam operated sequential timer. The advancement mechanism uses a combined arm and drive spring assembly laterally displaceable in a channel track of determined limits. The drive spring which supplies the force necessary to move the arm is secured thereto at a bias location so as to provide a pivotal force about an associated cam follower. A motor, connected to a suitable power source, is mounted on a dust cover attached to the rear plate or switch frame. This motor moves a gear train which in turn is adapted to rotate a multi-lobed cam at a rate determined by the gear train. A guidance channel is cut in the frame or rear plate and extends laterally adjacent the rotating cam. This slot has a predetermined extent determining the limits in which the arm of the mechanism is moved laterally as a roller cam follower rides along the rotating cam surface. The arm has a hook portion to which a tension spring has an end attached While its other end is connected to a post mounted on the frame. The finger end of the arm is placed against a ratchet wheel so that when the roller or follower moves along the associated cam surface, the arm is enabled to move consecutively along the teeth of the ratchet wheel. At the same time as the roller and arm are displaced laterally in the guidance channel, the tension spring is stretched so that when the follower comes to a desired portion of the cam surface, the force thus accumulated moves the arm against the ratchet tooth to rotate the ratchet by one step. The force applied to the ratchet teeth is thus accomplished in a reciprocating manner by having the arm move sidewise along the channel and by stretching the spring an extent determined by the length of the channel. The stored energy is released to the arm so as to advance the wheel. Essential in the operation of the advancement mechanism is the positioning of the slot cut in the frame. This is so because the position of the slot with reference to the horizontal center line of the cam determines the speed or duration of time in indexing or rotating the ratchet Wheel.

Referring now to FIG. 1, there is shown a motor 10 for transmitting its force to a drive pinion 11. Pinion i1 is coupled to a gear 12 which transmits its force to a lobed cam 13 of a predetermined configuration. As the cam rotates, it moves a cam follower assembly 14. The

assembly 14 comprises a roller 3% held in a bracket 31 integrally joined to a flat ratchet moving arm 18. This arm 1% is held in a plane parallel to the rear plate of the timer switch. Arm 18 has an end finger portion 32 which is bent at a right angle and is integrally joined thereto. Finger portion 32, as seen, is placed against teeth 33 of a ratchet wheel 20 which drives the shaft 34 which turns the switching cams (not shown). The movement of shaft 34 thus imparts a step by step movement to the cams as determined by the motivation of the ratchet wheel.

As stated, when cam 13 rotates it moves the cam follower assembly 14. Adjacent the lobed cam, there is formed a cam follower guidance channel 38 formed in the rear plate. The guidance channel is constructed of a determined configuration, essentially rectangular, with side walls 4%, 4-1 and end walls 42 and 43 establishing the width and extent thereof for a roller coupling which is contained therein. The cam follower roller 30 is slidably coupled to the channel and is held therein by means of a O ring so that when the cam rotates, and as roller 30 rides along the periphery or cam surface, the entire follower assembly will move in a horizonal, lateral direction. The assembly, including the roller bracket and arm will move in a sidewise direction in the guidance channel to an extent limited by the walls thereof. The cam 13 has a rise section 44 and a drop section 45. The movement of the ratchet wheel is accomplished intermittently through the movement of the escapement arm 18 against the teeth of wheel 20. The arm has an end of a tension spring 18 connected to a portion 19 thereof while the other end of the spring is connected to a post 15 held in rear plate 16. As the cam rotates and the follower assembly is moved sidewise in its guidance channel 38, the tension spring is cocked and energy is stored therein for activating the arm with relation to the ratchet wheel. In the embodiment shown in FIG. 1, the arm is used to thrust against the ratchet wheel, while the embodiment in FIG. 4 utilizes the energy in a pulling manner. Thus the ratchet is capable of being activated in either a thrust or pull manner. If the thrust operation is desired, FIG. 3 illustrates how the spring may be cocked while the arm is brought away from the ratchet wheel. On the other hand, it is apparent from FIG. 4 that the cocking of the spring takes place in the pull embodiment when the arm is in engagement with the teeth of the ratchet wheel. Moreover, the speed of each intermittent movement of the wheel is governed according to the vertical placement relationship of the guidance channel with respect to the driven cam. FIGS. 3 and 3a illustrate the fact that if the guidance channel 38 is raised with respect to the cam 13, then the rate of activation of the arm is changed from that obtained when the channel is placed lower or substantially at the center line of the rotating cam. It can be thus stated that in the condition shown in FIG. 3, instantaneous drop off and indexing advance obtains while the cam rotates at a constant speed. In FIG. 3a, since the slot is moved up from the center line, the drop olf speed will decrease as the cam rotates at a constant speed. It follows then that the duration of time in indexing or advancing the ratchet is directly proportional to the distance of the slot away from the center line of the cam.

The embodiment shown in PEG. 1, for example, will emphasize the operational features of the intermittent advancement mechanism described supra. As the cam rotates it moves the entire cam follower assembly 14 in a cam track 38 in the rear plate 16 in direction A. This motion extends the tension spring 17 and moves the arm 18 so as to pull back over the next ratchet tooth on the ratchet wheel 21). The ratchet is prevented from backing up by a non-backup pawl 21. When the lobed cam 13 is rotated to a drop off point the cam follower assembly 14 is then released allowing the spring 17 to return the arm 18 to an index point which is limited by the end of the cam track 33 in the rear plate 16. The drive spring 1'7 which supplies the force through the arm 18 to the ratchet wheel 23 for advancement is secured to the arm in a bias location 19 so as to provide a pivotal force about the cam follower by the thrust arm to hold the thrust arm in engagement with the ratchet wheel. The above described action advances the ratchet one tooth which completes one movement of the advancement device which is again set up to start the next movement.

In the operation of the system, the cam 13 is shown as being a lobed construction, the cam face drop oif being radial. Cam 1% is fixed to a hub which also carries a drive gear 12 and is thus adapted to rotate at the same frequency as the gear. The gear itself is rotated by a pinion 11 driven by a synchronous motor 10 powered from a suitable source. This motor is mounted securely to a dust cover 23 which also acts to determine the center distance between the motor pinion and drive gear. Cam follower assembly 14 includes a tubular roller bearing 30 which fits in a sleeve 31 of the cam follower, and is con tained by a channel 38 for the arm.

At the drop ofi point of the cam, the cam follower with tubular roller bearing rolls smoothly down the radial face and is suppor ed and contained in channel 38 of the rear plate 16. The cushioning action of the cam track and radial drop oif face of the drive cam on the cam follower assembly with its tubular roller bearing is achieved by a resultant wedging action between the two cam surfaces.- The force of the drive spring is sufiicient during the smooth drop off to over drive the synchronous motor through the gear train. This cushioning action may then be described as a combination reaction between cam surfaces and inherent inertia of the synchronous motor. The change in function of the synchronous motor from drive to driven member further acts as a cushioning force to reduce shock not only by mechanical inertia but electro-rnagnetic dynamic braking.

The invention described above discloses embodiments which can be varied without substantially changing the patentable features hereof, and accordingly the scope hereof is to be determined by the appended claims.

What is claimed is:

1. An advancement mechanism for an intermittent timing device comprising a frame, a motor mounted on said frame connected to a suitable power source, said motor moving a gear train, a cam of a given contour activated by said gear train, a channel slot cut in said frame along side said cam, said slot having a predetermined extent, an arm slidably connected in said slot, a cam follower carried by said arm placed against the peripheral surface of said cam for moving said arm along said slot on the rotation of said cam, said arm having a spring hook hol ing means, a tension spring connected to said means and to a stud on said frame, said arm having an end placed against a ratchet having teeth to activate the same, said arm being moved away from said teeth and said spring being cocked during the rotation of said cam, said arm being placed against said teeth of said ratchet to move the same by said spring energy through a determined portion of said cam cycle, said cocking and releasing of the spring being accomplished as said arm is moved along said slot of said frame so as to give a reciprocating movement thereto.

2. An advancement mechanism for an intermittent timing device comprising a frame, a motor mounted on said frame connected to a suitable power source, said motor moving a gear train, a cam of a given contour activated by said gear train, a slot cut in said frame alongside said cam, said slot having a predetermined extent, an arm slidably connected in said slot, a cam follower carried by said arm placed against a surface of said camfor moving said arm along said slot on the rotation of said cam, said arm having spring hook holding means, a tension spring connected thereto and to a stud on said frame, said arm'having an end placed against a ratchet havinglteeth to activatethe same, said arm being moved away from said teeth and said spring being cocked during the rotation cycle of said cam, said arm being placed against said teeth of said ratchet to move the same under the urgency of said spring energy during a determined portion of said cam cycle, said cocking and releasing of the spring being accomplished as said arm is moved along said slot of said frame so as to give a reciprocating movement thereto.

3. An advancement mechanism for an intermittent timing device comprising a frame, a motor mounted on said frame connected to a suitable power source, said motor moving a gear train, a cam of a given contour activated by said gear train, a slot cut in said frame alongside said cam, said slot having a predetermined extent, an arm slidably connected to said slot, a roller carried by said arm placed against the peripheral surface of said cam for moving said arm along said slot on the rotation of said cam, said arm having a hook portion, a tension spring connected to said hook and to a stud on said frame, said arm having an end placed against a ratchet having teeth to activate the same, said arm being moved away from said teeth and said spring being tensioned during a portion of the rotation cycle of said cam, said arm being placed against said teeth of said ratchet to move the same when said arm is released by the cam and the arm is moved by the tensioned spring during the fall portion of said cam, said tensioning and releasing of the spring being accomplished as said arm is moved along said slot of said frame so as to give a reciprocating movement thereto.

4. An advancement mechanism for an intermittent timing device comprising a frame, a motor mounted on said frame connected to a suitable power source, said motor moving a gear train, a cam of a given contour activated by said gear train, a slot cut in said frame alongside said cam, said slot having a predetermined extent, a thrust arm slidably connected to said slot, a roller carried by said arm placed against the peripheral surface of said cam for moving said arm along said slot on the rotation of said cam, said arm having a spring holding hook portion, a tension spring connected to said portion and to a stud on said frame, said thrust arm having an end placed against a ratchet having teeth to activate the same, said arm being moved away from said teeth and said spring being tensioned during a portion of the rotation cycle of said cam, said arm being placed against said teeth of said ratchet to move the same When said arm is released by the cam and the arm is moved by the tensioned spring energy during the fall portion of said cam, said tensioning and releasing of the spring being accomplished as said arm is moved along said slot of said frame so as to give a reciprocating movement thereto.

5. An advancement mechanism for an intermittent timing device comprising a frame, a motor mounted on said frame connected to a suitable power source, said motor moving a gear train, a cam of a given contour activated by said gear train, a channel slot cut in said frame alongside said cam, said slot having a predetermined extent, a thrust arm slidably connected in said slot, a roller carried by said arm placed against the peripheral surface of said cam for moving said arm along said slot on the rotation of said cam, said arm having a hook portion, a tension spring connected to said hook and to a stud on said frame, said thrust arm having an end placed against a ratchet having teeth to activate the same, said arm being moved away from said teeth and said spring being cocked during a portion of the rotation cycle of said cam, said arm being placed against said teeth of said ratchet to move the same when said arm is released by the cam and the arm is moved by the spring energy during the drop portion of said cam, said cocking and releasing of the spring being accomplished as said arm is moved laterally along said slot of said frame so as to give a reciprocating movement thereto.

6. An advancement mechanism for an intermittent timing device comprising a frame, a motor mounted on said frame connected to a suitable power source, said motor moving a gear train, a cam of a given contour activated by said gear train, a guidance slot cut in said frame alongside said cam, said slot having a predetermined extent and stop limits, a thrust arm parallel to said frame slidably connected with said slot, a roller carried by an end of said arm placed against the peripheral surface of said cam for moving these against said arm being moved along said slot on the rotation of said cam, said arm having a hook portion, a spring connected to said hook and to a stud on said frame, said thrust arm having an end placed against a ratchet having teeth to activate the same, said arm being raised from tooth to tooth of said ratchet and said spring being extended during a portion of the rotation cycle of said cam, said arm being placed against said teeth of said ratchet to move the same when said arm is released by the cam and the arm is moved by the spring energy during a determined portion of said cam, said extending and releasing of the spring being accomplished as said arm is moved along said slot of said frame so as to give a reciprocating movement thereto.

7. An advancement mechanism for an intermittent timing device comprising a frame, a nrotor mounted on said frame connected to a suitable power source, said motor moving a gear train, a cam of a given contour activated by said gear train, a guidance slot cut in said frame alongside said cam, said slot having a predetermined extent and stop limits, a pull arm parallel to said frame slidably connected with said slot, a cam follower carried by an end of said arm placed against the peripheral surface of said cam for moving thereagainst, said arm being moved along said slot on the rotation of said cam, said arm having a bias locating hook portion, a tension spring connected to said portion and to a stud on said frame, said pull arm having an end placed against a ratchet having teeth to activate the same, said arm being raised from tooth to tooth of said ratchet and said spring being extended during a portion of the rotation cycle of said cam, said arm being placed against said teeth of said ratchet to move the same when said spring energy is accumulated during the rise portion of said cam, said extending and releasing of the spring being accomplished as said arm is moved along said slot of said frame so as to give a reciprocating movement thereto.

8. An advancement mechanism for an intermittent timing device comprising a frame, a motor mounted on said frame connected to a suitable power source, said motor moving a gear train, a eam of a given contour activated by said gear train, a guidance slot cut in said frame alongside said cairn, said slot having a predetermined extent and stop limits, a thrust arm parallel to said frame pivotably mounted in and slidable in said slot, a roller carried by an end of said arm placed against the peripheral surface of said cam for moving thereagainst, said arm being moved along said slot on the rotation of said cam, said arm having a biasing hook, a tension spring connected to said hook and to a stud on said frame, said thrust arm having an end placed against a ratchet having teeth to activate the same, said arm being raised from tooth to tooth of said ratchet and said spring being extended during a portion of the rotation cycle of said cam, said arm being placed against said teeth of said ratchet to move the same when said spring energy is released during the drop portion of said cam, said extending and releasing of the spring being accomplished as said arm is moved along said slot of said frame so as to give a reciprocating movement thereto.

*9. An advancement mechanism for an intermittent timing device comprising a frame, a motor mounted on said frame connected to a suitable power source, said motor moving a 'gear train, a cam of a given contour activated by said gear train, a guidance slot cut in said frame alongside said cam, said slot having a predetermined extent and stop limits, an arm moveable in a plane parallel to said frame slidably held within said slot, a

cam follower carried by an end of said arm placed against the peripheral surface of said cam for moving therealong, said arm being moved sidewise along said slot on the rotation of said cam, said arm having a biasing hook, a tension spring connected to said hook and to a stud on said frame, said arm having an end placed against a ratchet having teeth to activate the same, said arm being raised from tooth to tooth of said ratchet and said spring being extended during a portion of the rotation cycle of said cam, said arm being placed against said teeth of said ratchet to move the same when said spring energy is exerted during a determined portion of said cam, said extending and releasing of the spring being accomplished as said arm is being pivotably moved in said slot of said frame so as to give a reciprocating movement thereto.

10. An advancement mechanism for an intermittent device as in claim 9, wherein said guidance slot may be vertically adjusted with relation to said eam so as to determine the rate of drop of said follower from the periphery of said cam.

References Cited in the file of this patent UNITED STATES PATENTS 

1. AN ADVANCEMENT MECHANISM FOR AN INTERMITTENT TIMING DEVICE COMPRISING A FRAME, A MOTOR MOUNTED ON SAID FRAME CONNECTED TO A SUITABLE POWER SOURCE, SAID MOTOR MOVING A GEAR TRAIN, A CAM OF A GIVEN CONTOUR ACTIVATED BY SAID GEAR TRAIN, A CHANNEL SLOT CUT IN SAID FRAME ALONGSIDE SAID CAM, SAID SLOT HAVING A PREDETERMINED EXTENT, AN ARM SLIDABLY CONNECTED IN SAID SLOT, A CAM FOLLOWER CARRIED BY SAID ARM PLACED AGAINST THE PERIPHERAL SURFACE OF SAID CAM FOR MOVING SAID ARM ALONG SAID SLOT ON THE ROTATION OF SAID CAM, SAID ARM HAVING A SPRING HOOK HOLDING MEANS, A TENSION SPRING CONNECTED TO SAID MEANS AND TO A STUD ON SAID FRAME, SAID ARM HAVING AN END PLACED AGAINST A RATCHET HAVING TEETH TO ACTIVATE THE SAME, SAID ARM BEING MOVED AWAY FROM SAID TEETH AND SAID SPRING BEING COCKED DURING THE ROTATION OF SAID CAM, SAID ARM BEING PLACED AGAINST SAID TEETH OF SAID RATCHET TO MOVE THE SAME BY SAID SPRING ENERGY THROUGH A DETERMINED PORTION OF SAID CAM CYCLE, SAID COCKING AND RELEASING OF THE SPRING BEING ACCOMPLISHED AS SAID ARM IS MOVED ALONG SAID SLOT OF SAID FRAME SO AS TO GIVE A RECIPROCATING MOVEMENT THERETO. 